The present invention relates to packages for opto-electrical components, the term xe2x80x9copto-electrical componentsxe2x80x9d being used herein to designate in general those circuits, assemblies or sub-assemblies comprising electrical, optical as well as optoelectronic (e.g., photodetectors, laser sources, etc.) devices. Exemplary of such packages are transmitter/receiver packages for optical transmission systems.
Such packages must in general comply with a number of requirements which are at least partly conflicting among them. For instance, the package structure should provide all the external constant electrical connections both at radio frequency (RF) and DC, and optical feed-through, as well as mechanical protection. Flexibility in the internal layout is also an extensively felt need, in that such a layout should be preferably chosen depending on the configuration of components to be included in the device. Electrical connections should be ensured with a high degree of reliability, the same also applying to the mechanical structure of the package. Finally, assembling the package should be easy, leaving a reasonable degree of freedom of movement.
Such requirements do not appear to be satisfactorily met by prior art package solutions which generally are provided for a fixed design.
The object of the present invention is thus to provide an improved solution which better complies with the needs outlined in the foregoing.
According to the present invention, a package for opto-electrical components comprises a casing including (1) a chamber, (2) at least one of a set of electrical connections, and (3) an optical feed-through path between the chamber and the outside of the casing. At least one board or tile adapted to be housed in the chamber is adapted to carry the opto-electrical components. The board or tile adapted to be housed in the chamber creates a solid mechanical structure with the casing while providing electrical connections therewith.
The casing preferably includes: (1) a box-like portion defining the chamber, and (2) a base member supporting the box-like portion and having a protruding end carrying the set of electrical connections.
The electrical connections are preferably in the form of strip-like formations. The box-like portion preferably includes an opening defining the optical feed-through path. The opening is preferably positioned generally opposite the electrical connections. The casing is preferably molded electrical insulating material.
The casing also preferably includes a trench-like formation for receiving the board or tile that is adapted to be connected to the casing by solder.
The board or tile is adapted to be electrically connected to the casing by ball bonding or wedge bonding. The board or tile preferably includes a ceramic substrate and can be from an assortment of boards or tiles of different types.
The package structure of the invention provides all the external constant electrical ohmic connections (RF+DC), the optical feed-through as well as the required mechanical protection of the devices located therein. An interchangeable microboard allows flexibility in the internal electrical layout, which can be chosen in a wide gamut of alternative layouts depending on the configuration of the components to be included in the device and inserted in the package e.g. into a proper trench. Each microboard (or xe2x80x9ctilexe2x80x9d) includes tracks and pads appropriate for its supported components (e.g. integrated circuits, optoelectronic components, and so on) allowing a fully reliable ohmic electrical connection.
Preferably, the microboard is soldered to the package thus creating a reliable mechanical structure. Ohmic electrical connections between the microboard and the package are preferably provided through ball bonding or wedge bonding, depending on performance required. The components to be included in the package can at least partly be mounted on the microboard or tile before this is located in the package and soldered thereto, which results in an increased freedom of movement in assembling such components.
The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed descriptions of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings.